JP3255653B2 - Bonding method using crystalline glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding method using crystalline glass.

[0002]

2. Description of the Related Art A joining glass or a sealing glass is widely used for joining metals, ceramics, glass plates and the like (same materials or different materials). In these joinings, the glass is caused to viscously flow by heating to join the glass to the article to be joined. In recent years, especially in the field of electronic components and display tubes, parts made of metal materials and ceramic materials are joined by glass,
The need to form complex structures has arisen.

[0003] When such a structure is formed by glass bonding, several kinds of glass having different viscosities are usually used properly. First, bonding is performed using glass having a relatively high softening point in the first bonding, and then bonding is performed at a lower temperature using glass having a softening point lower by 50 to 100 ° C. in the second bonding. If the bonding is performed at the same temperature as the first bonding, the already bonded portion viscously flows again, the bonded portion moves, and a precise structure cannot be formed. For this reason, it is necessary to lower the bonding temperature every time the bonding step is performed. For a complicated structure having a large number of bonding steps, the bonding temperature is too low and cannot be adapted.

For such a more complicated structure, crystalline glass is used. Crystalline glass is crystallized at the time of bonding or after bonding and does not viscous flow even if reheated at the same temperature, so that it can be used for bonding a complex structure having many bonding steps.

[0005] Crystalline glass is usually used in powder form. The powdered crystalline glass is mixed with an organic binder or an organic solvent to form a slurry, which is then applied to the joints by screen printing or a dispenser, or a sheet-shaped product or slurry is dried and granulated with a spray drier or the like. Then, the press-formed product is placed at the joint and heat-treated.

[0006]

When these powders are used, it is necessary to mix them with an organic substance, which involves gas emission caused by the organic substance at the time of joining. Also, since the glass is crushed into powder, it is contaminated with various impurities in the crushing process,
There is a problem that the structure is contaminated by these impurities. An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a bonding method that does not emit gas due to organic substances and does not require a pulverizing step.

[0007]

According to the present invention, a crystal nucleus component is provided.
The added PbO-based crystalline glass is formed into a molded body having a predetermined shape by heating, and the molded body is brought into contact with a body to be joined, heated to fuse the body to the body to be joined and crystallize. Contact
A bonding method using crystalline glass, characterized by forming a structure by repeating the combining step a plurality of times , and a crystal nucleation method.
The PbO-based crystalline glass to which the component is added is hot-formed into a shaped body having a predetermined shape, and the shaped body is sandwiched between a first bonded body and a second bonded body, and heated. contact of joining together the first and second object to be bonded is crystallized with fusing the molded article
An object of the present invention is to provide a bonding method using crystalline glass, wherein a bonding step is repeated a plurality of times to form a structure .

[0008] The crystalline glass is formed into a molded article having a predetermined shape by heating, under the condition that the crystal is not crystallized or the crystal hardly precipitates. The shape of the molded body is not particularly limited,
A wide range of rods, plates and the like are used. Crystalline glass is crystallized by heat treatment, and once crystallized, viscous flow properties of the glass are significantly lost. For this reason, in order to form the crystalline glass into a predetermined shape, it is necessary to form the glass at a temperature at which crystallization is difficult.

The crystalline glass Pyroceram (registered trademark) invented by Corning has a composition adjusted so that the crystallization temperature is considerably lower than the molding temperature and no crystallization occurs at the molding temperature. If crystalline glass suitable for such molding is used for bonding, crystallization starts before the glass reaches a viscosity sufficient for bonding, which is not preferable as the crystalline glass in the present invention. The crystalline glass used in the present invention is preferably a crystalline glass used for bonding (for example, # 7590 of Corning). The crystallization temperature of such a glass is set to be high in order to maintain a certain degree of viscosity at the time of bonding, and the glass is crystallized at the time of molding in a conventionally used glass molding method.

[0010] For this reason, it is rapidly cooled from the molten state and molded at the same time, or the molded product thus obtained is processed into a shape which can be easily molded in advance by cutting, polishing, etc., and this is reheated to form the molded product in a short time. By quenching, without crystallization, or in a state with very few crystals (semi-crystal)
It is preferred to mold with.

The object to be joined is mainly an inorganic substance such as metal, ceramics, glass, etc., but is not particularly limited as long as it can be joined with ordinary powdered glass. It is desirable that the thermal expansion coefficient of the article to be bonded and the thermal expansion coefficient of the crystallized glass be substantially the same in order to reduce the thermal distortion after cooling and achieve a strong bonding.

The composition of the crystalline glass for bonding is not particularly limited. However, since it is necessary to bond electronic parts and the like at a particularly low temperature, a PbO-based low melting point crystalline glass should be used for these parts. Is preferred. In joining, the formed body is placed on the joined body, heated and fused to the joined body, and crystallized during or after the fusion. This crystallization occurs through the generation of crystal nuclei. Usually, crystal nuclei are generated in a viscous state between a glass transition point and a glass softening point, and nuclei are generated from crystal nucleus components or impurities on the surface or inside of the glass. In addition, it is also possible to join the object to be joined by holding the molded body between the object to be joined and heating and fusing the molded body to the object to be joined and crystallizing. .

[0013] Unlike crystalline powder, crystalline glass has a rod-like or plate-like shape.
Crystals grow from the surface toward the inside of the glass, and the crystals may be oriented. In order to avoid such crystal orientation, a crystal nucleus component such as TiO ₂ or ZrO ₂ can be added to the glass component.

[0014]

EXAMPLES PbO 79% by _{weight%, B 2 O 3 8%} , ZnO 10
%, SiO ₂ 2% and Al ₂ O ₃ 1% were weighed and mixed so that the glass had a composition of 2 kg after melting.
Put this glass raw material in a platinum crucible and heat it in an electric furnace at 1100 ° C.
For 2 hours. The glass is taken out of the electric furnace and 15
Glass was uniformly poured into an iron mold having a size of cm × 35 cm and a depth of 10 mm. The thickness of the poured glass is 6mm,
By visual observation after cooling, no crystal grains were observed on the surface or inside the glass, and a transparent glass plate was obtained.

Similarly, the mixture was prepared so as to become 3 kg after melting, and the glass melted in the same manner was poured into the same iron mold. The glass had a thickness of 9 mm, and after cooling, crystal grains were observed on the surface with the naked eye. Further, after the poured off the molten glass, while seeking measuring the surface temperature by a radiation thermometer, cooling the surface with blower from 550 ° C., it was continued to cool to 350 ° C.. This glass plate was a transparent glass plate with no crystal grains observed on the surface and inside by visual observation.

The obtained transparent glass was pulverized in an agate mortar to obtain a 100-mesh pass, and the thermal characteristics were examined by DTA. As a result, the glass transition point was 320 ° C and the crystallization temperature was 10 ° C / min. The onset temperature was 412 ° C and the crystal peak temperature was 483 ° C. The thermal expansion coefficient of the crystal after treating this powder at 450 ° C. for 1 hour was 98 × 10 ⁻⁷ / ° C. in the range of 30 to 300 ° C. A 5 mm square glass bar having a length of 200 mm was prepared by cutting and polishing from a 9 mm thick glass plate cooled by a blower. The surface of this rod is roughness #
Finished with 2000 abrasives.

The glass rod was used for an inner diameter of 30 mm and a length of 100 mm.
mm at a constant speed to a tubular electric furnace of 100 mm.
By drawing at twice the speed, it was reheated into a thin glass rod shape. The electric furnace has three temperature zones at 600 ° C in the center.
0 mm, and the temperature distribution at both ends decreases rapidly. When the feeding speed was 1 mm / min, the glass was already crystallized at the time of drawing the glass, and the glass could not be drawn. When the feeding speed was 3 mm / min or more, a transparent 0.5 mm square glass rod was obtained. This stick, 50
mm to obtain a glass rod for bonding.

A 6 mm thick glass plate formed by pouring is cut and polished on both sides to a thickness of 50 mm × 4 mm.
4mm x 0.5mm x 50mm by slice cutting
L, a glass plate for bonding. A glass rod for bonding is placed on a metal plate (426 alloy, 60 mm square, 0.5 mm thick, having a selective oxide film formed of chromium oxide on the surface).
Put 5 at mm intervals, put the same metal plate on top of this,
Bonding was performed by heat treatment at 450 ° C. for 1 hour.

Similarly, a glass flat plate for bonding is 6 mm
Five metal plates were joined at intervals. The peel strength of these bonded plates was 200 kg or more in each case, and a strong bond was formed.

To examine the thermal stability of these bonded plates,
In the electric furnace, one side of the metal plate of the bonded sample was fixed, one side was not fixed, and the metal plate was held vertically in the electric furnace and heated again at 450 ° C. for 1 hour. In this test, if the bonded glass softens and flows, one of the metal plates falls by gravity. No such slippage or deformation was observed in any of the bonded samples using the glass rod and the flat plate. As a result, it is considered that the bonding glass was sufficiently crystallized and became stable against the reheat treatment.

As shown in the present embodiment, it can be seen that a strong joint can be formed by the crystalline glass formed by hot working, and that it is stable against re-heat treatment. When the object to be bonded is a metal, strong bonding is achieved via an oxide film as in this embodiment, but this oxide film is formed beforehand and when formed by heat treatment at the time of bonding. There is. Even if an iron-based metal does not form an oxide film in advance, the oxide film is formed at the time of heat treatment and can be strongly bonded.

[0022]

According to this joining method, compared with the joining method using powder-based printing or sheet, it is possible to join in a clean state without contamination in the pulverizing step and contamination due to volatilization and burning of organic substances. is there. Further, since it is thermally stable, bonding can be repeated many times, and it can be suitably used for an electronic component having a more complicated structure.

Claims (2)

(57) [Claims] 1. A PbO-based crystalline glass to which a crystal nucleus component has been added is formed into a molded body having a predetermined shape by heating, and the molded body is brought into contact with an object to be joined and heated to heat the molded object. Repeat the bonding step to fuse and crystallize the bonded body several times
A bonding method using crystalline glass, characterized in that a structure is formed by forming the structure . 2. A PbO-based crystalline glass to which a crystal nucleus component has been added is hot-formed into a shaped body having a predetermined shape.
The joining step of sandwiching the first and second joined bodies between the first and second joined bodies and heating and fusing and molding the molded body to join the first and second joined bodies to each other is performed a plurality of times. repeat
A bonding method using crystalline glass, which comprises forming a structure .